Sonic well pump with lateral vibration dampener



Feb. 18, 1964 A. G. BODINE 3,121,395

SONIC WELL PUMP WITH LATERAL VIBRATION DAMPENER Filed March 16, 1960 3 Sheets-Sheet 1 INVENTOR ALBERT G. BODINE BY "W ATTORNEY' Feb. 18, 1964 A. G. BOBINE 3,121,395

SONIC WELL. PUMP WITH LATERAL VIBRATION DAMPENER Filed March 16, 1960 3 Sheets-Sheet 2 FIG. 7

FIG. 8

INVENTOR:

ALBERT G. BODINE ATTORNEY A. G. BODINE Feb. 18, 1964 SONIC WELL PUMP WITH LATERAL VIBRATION JAMPENER Filed March 16. 1960 3 Sheets-Sheet 3 I3] INVENTOR ALBERT G. BODI NE f ATTORINEY United Sites arent 3,l2l,395 SGNIC WELL PUMP WlTH LATERAL VEBRATIN DAMPENER Albert G. Bodine, Los Angeles, Calif. (7 377 Woodley Ave., Van Nuys, Calif.) Filed Mar. i6, 1950, Ser. No. 15,377 19 Claims. (Cl. NfS-76) This invention relates generally to deep well pumps of the sonic class, employing elastic waves transmitted along a solid elastic column, usually the tubing string, and more particularly to guide bushings for the elastic column or tubing string in such a pump. The pumping action in such a pump results from elastic waves transmitted along the tubing, as described in my prior Patent No. 2,444,912.

As disclosed in said prior patent, the elastic wave action is directed longitudinally of the tubing, and a sonic pump of this type will be assumed for Ipurpose of disclosure of the present invention.

However, it is to be understood that a sonic pump may also employ torsional waves in the tubing, and that the invention is applicable to a pump of the torsional wave type as well, though the necessity for the present invention in a torsional wave pump may not be as pressing as with the more common or original longitudinal wave type.

In the longitudinal wave form of sonic pump, alternating elastic waves of compression and tension are launched down the tubing by a mechanical alternating force generator or oscillator coupled to its upper end. These alternating or successive waves of compression and tension travel down the tubing to the lower end thereof, where they `are reilected, and then travel back up `the tubing. If the frequency of the force generator is properly related to the length of the tubing, the waves of compression and tension arrive back at the top end in phase with force impulses of compression and tension, respectively, then being delivered by the force generator, so that the new wave is reinforced by the returned original wave. Under these circumstances, longitudinal standing waves are produced in the tubing, and nodes and antinodes occur therealong. An antinode occurs `at the top and bottom of the tubing, and at half-wavelength spacing therebetween. The nodes occur midway between the antinodes. Operation in this manner is of great advantage, particularly in deep Wells, in view of an energy storage property in a standing wave system. In more shallow wells, it is not so important that standing waves be established, since the pump behaves satisfactorily under travelling wave conditions. In either case, at any given instant, certain portions of the tubing are under compression, and therefore longitudinal elastically contracted, while other por-tions of the tubing are under tension, and longitudinally elastically elongated.

The transmission of such a longitudinal wave pattern along the tubing, wherein regions of the tubing elastically elongate and contract, results in a strong proneness for the column to vibrate laterally. Vibration amplitudes up to 1A are common, and may reach v1/2". The lateral vibration is parasitic in nature, its energy being derived from the longitudinal wave, and therefore resulting in a large subtraction from useful longitudinal wave energy. lSuch lateral vibrations are due in part to simple column compression phenomena, it being known that a long column under compression will tend to buckle. -In the sonic pump, the compression pulse is applied only momentarily, as mentioned above, being immediately followed by a tension pulse, which is then again followed by a compression pulse, and so on in sustained repeated cycles. The cyclic repetition of compression results in cyclic column buckling. The cyclic buckling appears, then, asa lateral vibration.

Another cause of lateral vibration is that the column is ICC never perfectly straight. Therefore, when the column is 4alternately pushed Aand pulled at one end, a lateral component of vibratory movement is generated simply because the column is not straight.

Additional cause of parasitic lateral vibrations include slightly crooked threads where the pipe joints screw together, unequalness in wall thickness of the pump tubing, secondary unbalances in the oscillator which generates the longitudinal wave, etc.

The most successful prior technique for preventing lateral vibration in the tubing has been the installation of yguide bushings on the tubing, with their peripheries in engagement with the pump casing. These bushings have sometimes included resilient inserts iu an attempt at damping, or for insulation of the vibration from the casing. The resilient inserts were elastically quite stiff, and therefore presented a high mechanical impedance, and were inadequate as regards damping factor. When used at sufficiently close spacing, however, these prior guide bushings have `been `found useful in holding the lateral vibration down to a tolerable amplitude by a brute force yform of technique. As an illustration of the large number and close spacing found necessary in field experience with this earlier type bushing, it has been usual to use three bushings per 3() foot tubing length, excepting near the nodes of the wave system, where four bushings per tubing length were used.

This previously known brute force bushing system, however, has some serious disadvantages. One of these is the large number and close spacing of bushings found iu field experience with the pump to be absolutely necessary to do the job. One factor here is the very high cost of the large number of bushings previously demanded. Another is the awkwardness in storing tubing lengths carrying so many bushings on the storage rack because of the space requirements thereof. Still another disadvantage in a sonic pump is that so many bushings sometimes give trouble by causing the liquid phase to condense `out of the gas column travelling up the casing annulus around the outside of the tubing.

The primary object of the present invention is the provision of an improved bushing system capable of restraining lateral vibration with far fewer bushings..

In studying this problem I made a surprising and important discovery with a different approach. 1 found that lateral tubing vibration can be completely controlled with only one-third as many bushings as before by use of a bushing provided with certain definable mechanical impedance characteristics in relation to the lateral wave impedance of the tubing and the energy content of the lateral wave to be combatted.

The invention was made through application of the irnpedance concept, and an understanding and broad definition of the invention requires a consideration thereof. Mechanical impedance is defined as the complex quotient of force and velocity. As regards the lateral wave mechanical impedance of the tubing, the force is that with which the tube moves laterally in its lateral vibration and the velocity is the velocity of lateral tube displacement. The mechanical impedance of the bushing is the complex quotient of the force of elastic resistance offered thereby to the tubing and the velocity of bushing displacement when moved by the tubing. `Mechanical impedance may further be defined by the complex expression Z=R[]'X, where Z is impedance, R is friction resistance or damping and X is the frictionless component of impedance known las reactance, j being the imaginary number The factor X, reactance, is the algebraic sum of inertial and elastic reactances, and in the present instance is predominantily elastic. Elastic reactance is directly proportional to elastic stiffness, and inversely proportional to wave frequency.

The present invention has a dual concept, the first part of which is that the mechanical impedance of the bushing be generally matched to the mechanical impedance of the tubing for the lateral vibration to be combatted. The second part of the concept is that the frictional, damping, or energy dissipative component R of the mechanical impedance of the bushing be of an order to dissipate continuously the energy of the lateral wave. This dual concept indicates, first, a bushing that is resilient and somewhat soft or yielding in character such as will vibrate freely in step with the lateral vibration of the tubing and at the same time receive maximum energy therefrom; and second a bushing physically formed or configured to contribute an amount of friction to continuously dissipate the lateral wave energy received from the tubing. This amount of friction means that the bushing is critically damped. In this connection, it should be understood that the required damping factor R is not that capable of absorbing continuously an amount of lateral wave energy such as might be built up in a lateral standing wave system should such a system be permitted to develop, but is a factor sufficient to dissipate lateral wave energy at the rate generated, or bled from the longitudinal wave.

In the past, sonic pump tubing bushings have invariably been characterized by substantially more mechanical impedance than the mechanical impedance of the tubing for lateral vibration, particularly in the component of elastic reactance. Thus they have been overly hard and stiff, and capable of acting only in brute force fashion. This means that they have stily opposed Vibration at their point of engagement with the tubing. This, however, has not really stopped the vibration, but merely shifted the wave pattern thereof, much like the fingering of a violin string practiced by a violinist. Lateral vibration, in the prior system, is reduced at the bushing, and a node tends to appear thereat. Then, because of zero or small amplitude vibration at the bushing, the necessary Wave energy dissipation would not occur within the bushing even if the bushing possessed internal friction properties. Thus large numbers of these relatively hard or high impedance bushings have been required to control lateral vibrations; and the control attained has been through the route of stiff, closed-spaced opposition to lateral movement. This condition is characteristic of the bushings disclosed in my Patent No. 2,444,912 and also those disclosed in my Patent No. 2,706,450. In the first 'of these patents, resilient bearings were placed inside casing anchoring sleeves, which were located at nodes of the longitudinal standing wave. These were found to be too far apart, of too great mechanical impedance, and of too little energy dissipation factor, for control of lateral vibration. It was found that by using many of the units, e.g., several per 30 foot tubing length, lateral vibration could be controlled by the brute force method mentioned above. The bushings disclosed in my Patent No. 2,706,- 450 were also of overly great mechanical impedance, by reason of use of too hard a rubber, and by precompression of the ribs thereof, by the external bearing ring, which made the ribs overly stiff. They were also of inadequate internal friction, and failed to approach critical damping. These devices thus also stifly oppose lateral vibration of the tubing to too great an extent, and shift the wave pattern so that a node tends to appear at the bushing, and dissipation of large lateral wave energy Within the bushing does not occur. This is in contrast with the present invention, wherein the impedance of the bushing is made substantially as low as that of the tubing, so that the tubing remains free to seek and vibrate in its natural pattern, notwithstanding the presence of the bushings. The natural lateral wave pattern is then attenuated by energy dissipation Within the high friction bushings located at points other than the nodes of the wave pattern.

Directing attention again to the energy dissipation or friction factor R, it will be seen that it is not sufhcient merely that the overall mechanical impedance Z of the bushing be of the order of that of the tubing, but it is also necessary that the energy dissipation factor R be sufficient to contribute the all-important critical damping.

The desiderata are, then, bushings of mechanical impedance Z not substantially greater than that of the laterally vibrating tubing, preferably of the same order as that of the tubing, and having a frictional or energy dissipative factor R sufficient to absorb and dissipate lateral wave energy at the rate received from the tubing. The latter factor may be described otherwise by saying that the bushings contribute sufficient friction to be critically damped, and to critically damp the laterally vibratory system. The bushing of the invention may be said to have a damping factor R which is at least criticaL It has been mentioned above that the damping factor of the bushing impedance does not have to be as great as to attenuate the level of energy that can be stored in a lateral standing wave system, if permitted to developed, and need be only great enough to dissipate the lateral wave energy as generated continuously, or bled from the longitudinal wave system. This then prevents the lateral wave from being built up in the rst place, before a strong lateral standing wave, with large energy storage property, can develop. Moreover, I have discovered that the degree of acoustic coupling between the parent longitudinal wave and the parasitic lateral wave increases with lateral wave amplitude. Therefore, the present invention, holding the lateral vibration down to low amplitude, in an initial low energy state, is particularly advantageous in that high lateral wave energy states never develop, and extreme snubbing effort is at no time required. In this general connection, it is of interest to note that the correlation between the very large wave energy desirably stored in a longitudinal wave system comprised of a pump tubing in a well of the order of a mile or more deep, and the very substantial parasitic wave energy which can become undesirably stored in a detrimental lateral wave system in such pump tubing, has presented a unique problem, the only really good solution for which, to my knowledge, has been furnished by the present invention.

The guide bushings of the invention can be composed of resilient rubber, plastic, or other resilient material. 'Ilhe characteristics of the invention can be in such bushings through Iappropriate selection from and adjustment of la number of variables controlling overall impedance Z and the Ifiui'otion component R thereof. Rubber ordinarily used for mechanical parts, such as bearings, rnbber mounts, etc., generally has la Shore hard. ness of or better. An ordinary cylindrical tubing guide bushing of snch Shore rating would be too hard; and would also lack sufficient internal friction. 'It would still fail for like reasons if composed of rnlater-ial of Shore 60. `Conceivably, a platin cylindrical bush-ing could be nrade soft enough, could be of a special rubber composition having sucient internal friction, and could be made long enough, to have fthe specified impedance characteristics of the invention considered in its broadest aspect. However, this approach does not appear Ito be entirely practical at this time, particularly because of undue length requirement. I therefore introduce, as further features of invention, a number of additional features, which may be used singly tor in combination. Thus special geometrical shapes and configuration are provided leading to large cyclic bending and therefore increased internal friction. Forms 'are provided in which pontions of the bushing rub frictionally on other portions of the bushing, Ior lon the casing. Devices are provided causing frictional rubbing on 'the pump tnbing. Bushings or other fonms are provided with inclusions of high friction material, such as bodies of viscous substances. By forming the bushing -in the natnre of a rubber spider, i.e., a hub with radial ribs or legs, added flexibllity and resilience is grained, and with rubber that is suiiiciently soft, overall impedance is ldesirably reduced. However, even with a Shore hardness as low las 60, such a spidertype bushing, of reasonable length, but without special additional lfeatures, still possesses somewhat too much overall impedance, and/or 'too little friction. 'Il-1e impedance characteristics desired of the invention may be practically attained, however, by `adding special ilexing land iriction features 4to this soft rubber spider form of bushing. For example, the ends of the legs of the spider may be formed with parallel slots, making the structure more flexible, land :the resulting leaves, liaps or fingers capable of bending relative to one another, as well as of rubbing friotionally on one another. The additional flexibility 4lowers the overall impedance, while the bending and rubbing increases the rtriotional component of impedance. A bushing of this geometry, typically cornposed of rubber of a Shore hardness of 60 to 70, has been found to attain the impedance :characteristics of the invention and to be an eminently satisfactory device.

I have also vfound that a readily controlled vari-able, useful in applying lthe invention, is the composition of the bushing. Thus the invention may be practiced by making a spider-type Ibushing of lso-it enough material, eg., Shore 60-70, and incorporating adequate frictional or damping material therein. The yfrictional material may be dispersed particles of divided material, such as sawdust, or bodies of viscous damping material such as tar or pitch.

The invention contemplates Various other physical forms of guide bushing, Iand very broadly and generically, the heretofore described special impedance characteristics of the invention, rather than specific physical configuration or coni-position, are the basic essence thereof. However, invention resides in physical coniigunation yand/or composition in a nurnber of variational embodiments of the invention, some of which will be described with reference yto the accompanying drawings, in which:

FIG. 1 is la longitudinal sectional view, with portions broken away, of the upper end portion of a sonic pump installation equipped with the improvements of the present invention;

FIG. 2 shows the lower `end portion of the pump of FIG. 1;

FIG. 3 a sectional view of a tubing coupling and valve, the section being taken on line 3-3 of FIG. 1;

FIG. 4 is a transverse section taken on line 4 4 of FIG. 2, and showing a form of spider bushing in accordance with the invention;

l1FlG. 5 lis a perspective view ofthe bushing of FIG. 4;

FIG. 6 Iis a fragmentary view of a portion of -a spider bushing similar to FIG. but showing a modiiication;

FIG. 7 is la plan View of a spider bushing somewhat simi-lar to that of FIGS. 4 and 5, :but showing a modification; f

FIG. 8 is a side elevation view of the bushing of FIG. 7;

FIG. 9 is ya perspective view of another specie-s of spider bushings in .accordance with the invention;

FIG. l() is a perspective view of still another species of spider bushing in accordance with the invention;

FIG. 10c is a fragmentary plan view of -a portion of the bushing of FIG. l0;

FIG. ll is a plan view of another .type of bushing in accordance with the invention;

FIG. l2 is a detail section taken on line 12-12 of FIG. 11;

FIG. l3 is la side elevational view, with parts broken away, `of .another form yof lateral vibration suppression means mounted on the pump tubing;

FIG. 14 is a plan view of .fano-ther type of device in accordance with rthe invention; and

FIG. l5 is la side elevational View of the device of FIG. l4.

yIn FIG. 1 'an yoil well sonic pumping installation is shown, the well bore being shown to be lined part way down by surface casing 1l), While annnlarly spaced inside casing 10 is production casing 11, inside of which has been suspended fthe steel pump tubing 12, made up typically of 30 foot tubing lengths 13 connected by couplings 14. Mounted `at the top of casing 10 and 11 is a suitable casing head, conventionally indicated at C, and the pump tubing 12 extends upwardly :through said casing and has mounted at its upper end la longitudinal wave or vibration generator G. This generator G comprises a housing 16 containing a device for vibrating the upper end of the :tubing 12 is la direction longitudinal of the latter, thereby exerting la vertical oscillating force upon the upper end :of fthe tubing.

The means for generating the vibratory action is here shown of a simple type embodying meshing oppositely rotating spur gears 17 carrying eccentric weights 18, which balance out horizontal vibrations but areadditive to produce a substantial resultant 1oscillatory force in a vertical direction. The generator has ra driving pulley 19 driven through belt 20 from electric drive motor 21. Since this vibrator is employed to generate elastic waves in the pump tubing which are of ythe same nature as sound waves, and ltravel with the speed of sound waves in the pipe, I may properly refer to this vibrator as a sonic wave generator.

Extending upwardly from casing head C, at an annular spacing outside tubing string 12, is a pipe section 24, and screwed onto the upper end of the latter is a head 25 having at the top a flange 26. Bolted to flange 26 is a tiange 27 of a tubular fitting 28 on the bottom of the lower platform 29 of a spring support device 30 for the tubing string and vibration generator G, the tubing being packed by a stuffing box at 29a. The spring supporting device 30 includes an upper plate or platform 31, supported from lower platform 29 by a plurality of coil springs 32, vertical guide rods 33 being used inside these coil springs, as indicated. The guide rods 33 may be set rigidly in the member 29, and project through suitable openings in the member 31 with a free sliding tit. A collar 35 near the upper end of the tubing string overhangs an upwardly facing seating shoulder 36 formed in the member 31, and it will be understood that the weight of the tubing string and vibrator G are transferred to the member 31, and through spring 32, to the platform 29. This member 29 is, of course, supported from the casing head.

A delivery tting 4t) at the top end of the pump tubing, between the tubing and the generator G, delivers production fluid to production line 41. The tubing string may be provided with one or more bleeder openings 47 of such size as to bleed a small fraction of the production fluid into the space between the tubing and the production casing, in order to lubricate the later described guide bushings. The pump tubing contains check valves such as indicated at V, preferably one within each tubing coupling 14, and such valves comprise a tubular iluid displacing member Si) and a check valve element 52 seating at the top end of the fluid passage S3 through the member 5l). Stop shoulders S4 limit upward displacement of the valve elements 52.

The operation of such a pump is fully set forth in my aforementioned patent. It will be recalled that periodic elastic deformation waves of tension and compression travel down the pump tubing as a result of the vertical alternating force applied to the upper end thereof by the generator device G. These waves set local portions of the tubing into vertical oscillation through an amplitude up to say The tubular valve members 5t) carried by the tubing accordingly have this vertical oscillation. On each down stroke, the members 50 travel with an acceleration suiiiciently great to separate'from the valve elements 52, and fluid displaced by the members 50 travels upwardly therethrough and past the then unseated valve elements 52. On the up-stroke, the valve elements 52 seat, and the column of well fluid thereabove is elevated. The column of well tiuid above valve elements 52 does not substantially drop during the downstroke of the member 52, because the acceleration of the latter considerably exceeds the acceleration of gravity.

Illustrative guide bushings in accordance with the invention are shown at 60 in FIGS. l, 2, 4 and 5, one shown as located at the mid-point of each tubing length. Each of these bushings comprises a relatively soft, resilient, rubber spider, composed of oil resistant synthetic rubber. A Shore hardness as low as 60 to 70 is suitable. The spider comprises a hub 61, with a bore 62 having a normal diameter such as to afford an interference iit with the tubing. The spider is forced on over the tubing, and lits tightly thereon. Radiating from hub 61 are a plurality of somewhat tapered legs 64, in this instance five in number. Each leg is formed with a plurality of parallel, vertical slits or cuts 65, typically four or five in number, extending inwardly from its outer end face 66, thereby providing a plurality of relatively flexible, close-spaced parallel liaps or leaves 67. The slits 65 may be formed by saw cutting; or the entire bushing may be formed in one step by extrusion. In the rst case, the slits are relatively narrow, as illustrated. When formed by extrusion, the slits may be somewhat wider, e.g., double that indicated in FIG. 4. The length of the legs 64 may be such that the circle defined by the outer ends thereof has a diameter somewhat larger, e.g., 1/8", than the inside diameter of the casing. Accordingly, for such a case, the liexible leaves 67 are bent or warped somewhat when introduced into the casing, and so deflected into mutual lateral contact. This case is not illustrated in the drawings, but will be readily understood.

This spider bushing as thus described has the impedance characteristics dictated by the invention. The rubber is relatively soft, and the geometry of the spider affords substantial flexibility. The relatively flexible leaves 67 in lateral surface contact with one another, flex and bend under the inliuence of small amplitude lateral tubing vibration, and slide and rub on one another, as well `as working somewhat on the casing. The considerable flexing and bending of the leaves introduces substantial internal friction, and the rubbing of the leaves on one another and on the casing during lateral motion of the tubing introduces very substantial surface friction.

While the above described system, with the spider legs somewhat oversize for the casing bore, is generally preferred, I have also found that the bushings of FIGS. 4 and 5 function satisfactorily when of the same size as the internal diameter of the casing, or with a small clearance between the ends of the legs of the spider and the casing. For example, the circle defined by the ends of the spider legs may be JAG less in diameter than the inside diameter of the casing. In such case, of course, and particularly when the well is not entirely straight, one or more legs on at least one side of the bushing will generally actually contact the casing. In any event, when lateral vibration tends to appear, and develops to an amplitude of say one sixteenth inch, or slightly more, the leaves on the ends of the legs of the spider will be in frictional bending and sliding contact, so as to damp the vibration, and prevent high lateral energy states with high lateral vibration amplitudes.

By the means described, the spider bushing to FIGS. 4 and 5, in either of the cases described above, develops and presents a frictional dissipative factor R for the mechanical impedance of the bushing which is sufficient to absorb the lateral wave energy received from the tubing, and which thereby critically damps the lateral wave. At the same time, the bushing is sufficiently soft and flexible that the overall mechanical impedance Z of the bushing is adjusted to be approximately that of the laterally vibratory pump tubing, or at least not substantially greater than the impedance of the tubing.

The bushing then centers the tubing, and, in accordindicated in dotted lines.

ancewith principles set forth in the introductory portion of the specilication, damps and controls the lateral wave energy in the tubing, and prevents its building up to an undesirable lateral vibration energy state.

FIG. 6 shows a modification of the bushing of FIGS. 4 and 5, according to which one of the legs 68 is longitudinally split, as at 69, in the plane of a central saw cut 70, and is fastened closed by bolt 71 and nut 72. This expedient facilitates installation of the bushing on the pump tubing.

FIGS. 7 and 8 show a modified bushing 72 of the spider type, again comprised of soft rubber hub 73 and legs 74 (Shore 60-70), but wherein the legs are formed with horizontal, parallel saw cuts 75 instead of the vertical cuts of the preceding embodiment, thereby forming horizontal leaves 76. The circle defined by the ends of the spider legs is in this case made of considerably larger diameter than the inside of the casing, e.g. 1A to 1%, so that the leaves are bent upwardly when the bushing is run into the casing, and thereby folded into contact with one another, their extremities turned towards or into parallelism with the casing. Under the influence of lateral vibration, the leaves 76 flex and rub on one another and thus develop both internal and surface friction. This embodiment has the same general impedance characteristics of the first described embodiment.

FIG. 9 shows a modified form of the spider type bushing of FIGS. `4 land 5, composed of rubber of the same degree of softness, and in the form of a hub 8) adapted to fit over the pump tubing and radial legs 81 which are either engageable with the casing or at a slight clearance therefrom. The legs S1 in this case are not leaved at the ends, and friction to the requisite extent is obtained by inclusions of foreign material contributing substantial internal friction upon vibratory bending of the legs. In

.the specific embodiment shown, there is placed in each leg of the spider, running through it from top to bottom, a body 83 of a viscous substance such as tar or pitch. Lateral vibration of the casing-confined spider by the pump tubing causes flexing of the spider legs, and therefore shear within the viscous bodies 83. The internal friction so developed affords the necessary critical damping or dissipation factor R for lateral vibration, in combination with an overall mechanical impedance Z conforming to the basic requirements of the invention.

FIGS. 10 and 10a show another bushing 85 in accordance with the invention, being a modified spider type, and

capable of being composed of rubber, plastic or other resilient material of good internal friction property. Because of the geometry of the spider in this case, the necessary low mechanical impedance can be attained with ysomewhat harder rubber than that used for earlier ernbodiments, such as Shore to 90, or even a fairly stid plastic, such as nylon. The spider in this case has a hub 86 bored to slide on over the pump tubing with an interference lit, and a plurality of spider legs 87, in this case four in number, having inner portions 88 extending or radiating substantially tangentially from the hub, and thinner outer portions 89, in the nature of leaves or aps, joining portions 88 in an obtuse angle bend at a knee 90. When unconiined by the casing, indicated in phantom lines at 91, the leaves 89 normally assume the position When inserted in the casing, the leaves 89 are bent to the position shown in full lines about knee 90, and the outer surface thereof conforms to the circular interior wall surface of the casing and lies in contact therewith. The outer surfaces of the leaves 89 are preferably formed with parallel vertical ridges 92 for maximum friction against the casing for lateral vibration, while at the same time minimizing friction on the casing for longitudinal vibration. Also, preferably, layers of fabric 93 are incorporated in the legs of the spider through the tangential portions 87 thereof,

'around the bend, and for a distance through the leaves 89, both for reinforcing purposes, and to increase internal friction.

annees When the bushing is subjected to lateral vibration from the tubing, the knee portions 9i) of the legs of the spider move cyclically against and from the casing with a small amplitude, causing a cyclic straightening of the angle between leg portions 88 and 89 and a vibratory sliding movement of the latter circumferentially of the casing, in friction contact therewith. Friction is thus developed internally by bending of the legs of the knee regions 90, and externally by rubbing of the leaves 89 on the casing. The leaves are relatively iiexible as regards the described bending action, and low impedance, of the order of that of the tubing for lateral vibration, is readily attained. At the same time, friction is high and critical damping also readily attained. Nylon is especially advantageous because of its high hysteresis, and consequent high energy dissipation factor.

FIGS. 11 and 12 show another embodiment of bushing in accordance with the invention, of a somewhat different type. In this instance, a rubber hose is cut laterally approximately two-thirds of the way through at a plurality of spaced points therealong, so as to form hose-loops 96, and the resulting product is bent into a ring about the pump tubing 97. A clamping band 98 is run through the loops entirely around the ring, adjacent the unsevered band portion 99 of the hose, and is drawn tightly to clamp the assembly about the pump tubing by means of a hose clamp 1%. A device so made has flexibility and softness, of an order to conform with the mechanical impedance requirement of the invention, and the flexing of the hose loops that occurs upon lateral tubing vibration generates sufficient internal frictional loss within the hose loops as to conform to the energy dissipation factor R as further required by the invention.

In FIG. 13, I have shown another device conforming to the broad invention, in this case in the nature of a hose 11) wrapped spirally about a short length of pump tubing 111, and understood to engage, or be at only slight spacing from, the walls of the casing. Hose 110 is clamped at its upper and lower ends to the tubing by means of clamping bands 112, and it may be filled with a viscous damping material 113, composed of such a material as tar, pitch or the like. This embodiment of the invention also conforms to the impedance requirements of the invention, the spirally wrapped tarlled hose being sufficiently soft and yielding to provide a low mechanical impedance as called for by the invention, and the viscous material 113 contained within the hose contributing the necessary damping factor to assure critical damping of lateral wave action.

FIGS. 14 and l5 show one nal form of device conforming to the impedance requirements of the invention, composed in this case entirely of steel. The device in this instance has at the top a collar 120 adapted to encircle the pump tubing. The collar has two ends portions 121 and 121 connected by a bolt 124 and nut 125, which may be tightened to secure the device to the pump tubing. Extending downwardly from collar 120 are a plurality of legs 126, in this case three in number. Each of these legs 126 includes a downwardly and outwardly inclined portion 127 extending from collar 12), a vertically disposed portion 123 engageable with the casing, and charnfered as at 129 to conform somewhat to the curvature thereof, a portion 13) extending downwardly and inwardly below portion 123, and vertically disposed lower portion 131 which engages the side of the pump tubing. Upon lateral vibration of the pump tubing, individual legs 126 are moved repetitively against the wall of the casing. Upon each such occurrence, the legs tend to straighten out, causing the portion 131 thereof to slide vertically on the pump tubing. Large surface friction is thereby developed, of an order to critically damp the lateral vibration of the tubing. That is to say, the surface friction developed as described absorbs and dissipates lateral wave energy from the tubing at the rate received therefrom. The generally bow-shaped legs 126 are relatively flexible,

10 and Vthe overall mechanical impedance of the device is thus low, and conforms to the heretofore described impedance requirement of the invention.

A number of illustrative embodiments of the invention have now been described and illustrated. It will of course be understood that these are merely for illustrative purposes, and that the invention is conceived of as basic in nature and therefore embraces many changes in design, structure and arrangement within the scope of the broader of the appended claims.

I claim:

1. For use in a sonic well pump having a vibratory pump tubing annularly spaced inside a production casing, a suppressor for parasitic lateral vibration of the pump tubing comprising vibration receiving means adjacent the tubing tightly embracing and laterally vibratory with the tubi-ng, and resilient lateral vibration absorbing means extending youtward from said vibration receiving means and being engageable with the casing, whereby to undergo cyclic elastic deection between said vibration receiving means and the casing, said resilient lateral vibration absorbing means being structurally composed and arranged with physical qualities of flexibility `and friction in a combination aifording a mechanical impedance substantially as low as the mechanical impedance of the tubing for lateral vibration thereof and with a frictional energy dissipative component yielding critical damping for lateral tubing vibration.

2. The subject matter of claim 1, wherein the mechanical impedance of the suppressor is of the order of the mechanical impedance of the tubing for lateral vibration thereof.

3. The subject matter of claim` l, wherein said suppressor comprises a bushing of flexible rubber or the like in the form of a spider having a hub embracing the tubing and receiving lateral vibration therefrom, and flexible vibration absorbing legs engageable with the casing, said legs including liexibly bendable portions slidable on one another in response to lateral ltubing vibration to develop surface friction dissipative of lateral vibration energy.

4. The subject matter of claim 1, wherein said suppressor comprises -a bushing of flexible rubber or the like in the form of a spider having a hub embracing the tubing and receiving lateral vibration therefrom, and flexible vibration absorbing legs engageable with the casing, and frictional energy dissipative bodies embedded. on said legs.

5. The subject matter of claim 1, wherein said suppressor comprises a bushing of flexible rubber or the like in the form of a spider having a hub embracing the tubing and receiving lateral vibration therefrom, and flexible vibration absorbing legs engageable with the casing, said legs being formed with angle bends in a plane at right angles to the tubing forming regions of substantial cyclic elastic bending 'and internal friction in response to lateral tubing vibration.

6. The subject matter of claim 1, wherein said vibration receiving means comprises a band tightly secured about the tubing, and said resilient vibration absorbing means comprises a circular series of resilient flexible loops connected with said band and extending through the annulus between the tubing and casing for engagement with said casing.

7. The subject matter of claim 1, where said vibration receiving means com-prises a collar tightly secured about said tubing, and said resilient vibration absorbing means comprises a plurality of substantially bow-shaped resilient legs connected at one end to said collar, bowed therefrom into engagement with the casing, and returned into frictional sliding engagement with the tubing.

8. The subject matter of claim 1, wherein said suppressoicomprises a flexible hose wrapped spirally around the tubing and connected at each end thereto, the diameter of said hose being such as to substantially fill the annulus between the tubing and casing, and a body of Visco-us material within said hose.

9. For use in a sonic well pump having a vibratory pump tubing annularly spaced inside a production casing,

a suppressor for parasitic lateral vibration of the pump tubing comprising' a bushing of flexible rubber or the like including a hub for embracing `the tubing and receiving lateral vibrations therefrom, and vibration absorbing legs radiating from said hub for engagement with the production casing, said legs including iiexibly bendable portions slidable on one another in response to lateral tubing vibration to develop surface friction dissipative of lateral vibration energy.

10. For use in a sonic well pump having a vibratory pump tubing annularly spaced inside a production casing, a suppressor ttor parasitic lateral vibration of the pump tubing comprising a bushing of flexible rubber or the like including a hub for embracing the tubing and receiving lateral vibration therefrom, and vibration absorbing legs radiating from said hub for engagement with 4the production casing, the outer end portions of said legs being slotted Ito provide a plurality of flexible flaps with lateral friction surfaces adjacent to one another.

11. The `subject matter of claim 10, wherein said outer vend portions of legs are slotted vertically.

12. The subject matter of claim 10, wherein said outer end portions of said legs are slotted horizontally to form vertically bendable flexible flaps and wherein the diameter of the circle defined by the outer ends of said legs exceeds the interior diameter of said casing in such manner as to eifect vertical bending of the outer portions of said ilexible aps into frictional engagement with adjacent liaps. v

13. For use in a sonic well pump having a vibratory pump tubing annularly spaced inside a production casing, a suppressor for parasitic lateral vibration of the pump tubing comprising Ia bushing of flexible rubber or the vlike including a hub for embracing the tubing and receiving lateral vibrations therefrom, and vibration absorbing legs radiating from said hub for engagement with the production casing, and bodies of viscous frictional damping material embedded in said legs.

14. For use in ya sonic well pump having a vibnatory pump tubing annularly spaced inside a production casing, a suppressor for parasitic lateral vibration of the pump tubing comprising a bushing of flexible rubber or the like including a hub for embracing the tubing and receiving lateral vibrations therefrom, and flexible vibration absorbing legs radiating from said hub for engagement with the production casing, said legs being formed with bends therein in a plane at right angles to .the tubing forming regio-ns of substantial elastic bending and internal friction in response to lateral tubing vibration.

15. For use in a sonic well pump having a vibratory pump tubing annularly spaced inside a production casing, a suppressor for parasitic lateral vibration of the pump tubing comprising a bushing of resilient material including a hub for embracing the tubing and legs extending outwardly from said hub into engagement with the casing, said legs having inner portions extending substantially tangentially from said hub and flexible casing engaging leaves extending from said inner portions generally circumferentially of the casing and lying in engagement therewith.

16. For use in a sonic Well pump having a vibratory pump tubing annularly spaced inside a production casing, a suppressor for parasitic lateral vibration of the pump tubing comprising a bushing including a hub for embracing the tubing and iiexible and resilient legs extending outwardly from said hub to a distance normally located outside the casing, said legs being bendable inwardly for confinement inside the casing and having outer portions lying in contact with the casing and extending generally circumferentially thereof.

17. The subject matter of claim 16, wherein said outer portions of said leaves are vertically ribbed in regions thereof in contact with the casing.

18. For use in a sonic well pump having a vibratory pump tubing annularly spaced inside a production casing, a suppressor for parasitic lateral vibration of the pump tubing comprising a bushing including a hub for ernbracing the tubing and flexible, resilient legs extending outwardly from said hub generally tangentially thereof, said legs having knee bends towards said hub in the region of the casing and outer flap portions beyond said knee bends formed normally to extend outwardly beyond the circumference of the casing but bent inward by the casing and lying in frictional contact therewith and generally circumferentially thereof.

19. For use in a sonic well pump having a vibratory pump tubing annularly spaced inside a production casing, a suppressor for parasitic lateral vibration of the pump tubing comprising a length of rubber hose formed into an annulus about the pump tubing, means clamping said annulus tto said tubing, said annulus being formed with a series of cuts from its outer periphery toward but terminating short of its inner periphery so as to form a plurality of connected resilient loops, and said loops extending from the tubing into close proximity with the casing whereby to engage the casing during lateral vibration of the tubing.

References Cited in the tile of this patent UNITED STATES PATENTS 2,131,274 Crickmer Sept. 27, 1938 2,444,912 Bodine July 13, 1948 2,669,190 Mullins Feb. 16, 1954 2,672,383 Hamer Mar. 16, 1954 2,680,485 Bodine June 8, 1054 2,706,450 Bodine Apr. 19, 1955 

1. FOR USE IN A SONIC WELL PUMP HAVING A VIBRATORY PUMP TUBING ANNULARLY SPACED INSIDE A PRODUCTION CASING, A SUPPRESSOR FOR PARASITIC LATERAL VIBRATION OF THE PUMP TUBING COMPRISING VIBRATION RECEIVING MEANS ADJACENT THE TUBING TIGHTLY EMBRACING AND LATERALLY VIBRATORY WITH THE TUBING, AND RESILIENT LATERAL VIBRATION ABSORBING MEANS EXTENDING OUTWARD FROM SAID VIBRATION RECEIVING MEANS AND BEING ENGAGEABLE WITH THE CASING, WHEREBY TO UNDERGO CYCLIC ELASTIC DEFLECTION BETWEEN SAID VIBRATION RECEIVING MEANS AND THE CASING, SAID RESILIENT LATERAL VIBRATION ABSORBING MEANS BEING STRUCTURALLY COMPOSED AND ARRANGED WITH PHYSICAL QUALITIES OF FLEXIBILITY AND FRICTION IN A COMBINATION AFFORDING A MECHANICAL IMPEDANCE SUBSTANTIALLY AS LOW AS THE MECHANICAL IMPEDANCE OF THE TUBING FOR LATERAL VIBRATION THEREOF AND WITH A FRICTIONAL ENERGY DISSIPATIVE COMPONENT YIELDING CRITICAL DAMPING FOR LATERAL TUBING VIBRATION. 